Hydro-pneumatic press apparatus



' March 25, 1958 Fild Dec. 9, 1954 L. C. HUFFORD HYDRO-PNEUMATIC PRESS APPARATUS 3 Sheets-Sheet l INVENTOR. LEW/5 C. Hui-FORD 4] mew-y March 25, 1958 L. c. HUFFORD HYDRO-PNEUMATIC PRESS APPARATUS Filed Dec. 9, 1954 3 Sheets-Sheet 2 W I M. I w I E; 15?; :1: 21:: n m l l & Z 3? a m E 7 u 90v 3 5 i a WW 1 0 6 4 1 4 7 INVENTOR. lav/5 C HUFFOEO V ATTORNEY United States Patent 9 1C Patented Mar. 25, 1958 zezmss I-TYDRG-PNEUMATHI Panes APPAnA'rUs Lewis J. Hur'iord, Manhattan Beach, Calif., assignor of one-half to Lionel E. Weiss, Palos Verdes Estates, Calif.

Application December 9, 1954, Serial No. 474,207

lil Claims. (Cl. 60-545) This invention relates to a pneumatically-operated hydraulic press.

An object of the present invention is to provide a press apparatus in which high pressures are developed and in which said high pressures are all contained in the different components rather than in the piping connecting the components. Hence, all piping is under low pressure, the benefits of this feature being evident.

Another object of the invention is to provide a press of the character indicated that, although developing high pressures, obviates undue generation of heat. Therefore, the hydraulic fluid used, not being subject to high heat, does not oxidize.

A further object or" the invention is to. provide a hydropneumatic press that is capable of rapid operation at low, expense-saving horsepower, the same contributing to economical and commercially feasible operation in various industries or" which ceramic tile production is an example.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawings merely show and the following description merely describes, preferred embodiments of the present invention, which are given by way of illustration or example only.

in the drawings, like reference characters designate similar parts in the several views.

Fig. 1 is a diagrammatically arranged sectional View showing the components of a hydro-pneumatic press according to the present invention, the same being shown in retracted position preparatory to operative projection.

Fig. 2 is a similar but enlarged view of the hydraulic components of. the press and shown in operative projected position.

Fig. 3 is a sectional view of a modification.

The press that is illustrated comprises, generally, a pneumatically-operated reservoir 5 for hydraulic fluid, a pilot-operated check valve 6 controlling flow into and out of the reservoir 5, an operating unit 7 connected to valve 6 and comprised of a power unit 8 and a booster 9, a source of air pressure ill, a four-way or distributing valve 11 controlling flow of the pressure from source to components 5, 6 and 8, and a three-way valve 12, having a vent 13, controlling flow of pressure from source to the booster 9.

The reservoir 5 is shown as comprising a cylinder provided with end heads 21 and 22, a piston 23 operating in the cylinder and limited in its movement by the heads, and a hollow stem 24 extending from said piston through a suitable sealing guide 25 in head 21. Stem 24 is provided with a removable plug 26 which, upon removal, allows fliliru of cylinder 20, between piston 23 and head 22, with suitable hydraulic fluid 27. Because of the pressures developed in reservoir 5, the heads 21 and 22 are connected as by tension tie bolts 28.

Pressure air is adapted to be admitted into cylinder 20 between head 21 and piston 23. To this end, a master valve 29 is provided to convey and exhaust such pressure, the source 19 being connected thereto. Projection of piston 23 by air admitted through valve 29 causes displacement of hydraulic fluid 27 through connection 30 that connects the reservoir 5 with pilot-operated check valve 6. Valve 29 is vented to the atmosphere through vent 29a.

The valve 6 comprises a body 35 having an inner chamber 36 with which connection 30 communicates, a poppet valve 37 that opens to pressure in said chamber 36 and communicates said chamber with a chamber 38 beyond said valve, a cylinder 39 in the end of the body 35 opposite chamber 38, a piston 40 in said cylinder, and a stem 41 connecting valve 37 with piston 40. Springs 42 are provided to urge said piston in a direction to close valve 37 and it is these springs that are overcome by fluid 27 flowing past said valve into chamber 33. Said valve 37 may be opened against pressure in chamber 38 which is greater than the pressure in chamber 36. A pressure air connection 43 etfective on piston 40 will open valve 37 under such conditions.

The power unit 3 and booster 9 of operating unit 7 are interconnected by a body 5% having therein a chamber 51 that is in communication with chamber 38 of valve 6, there being a direct connection. between said body and said valve, as shown, so that chambers 38 and 51 constitute, in effect, a single chamber. Body 58 is further provided with a cylindrical passage 52 that is preferably centrally located.

The power unit 8 comprises .a cylinder 55 that is closed at one end by body 56. Said cylinder is provided with a flange 56 by means of which it is secured to a fixed member 57. The latter member typically comprises the crosshead of a press frame of any conventional design and,

per se, comprises no part of this invention. A piston 58 operates in cylinder 55, the same being connected to a ram 59 that extends through a suitable sealing gland 6i? in the end of said cylinder opposite to body 58. Between body 56 and piston 58, the cylinder encompasses, a hy draulic chamber 61 that is in direct communication with chamber 51 and between said piston 58 and gland there is defined an annular air chamber 62 to which is connected a pipe 63.

The projecting end of ram 59 is provided with a platen 54 that is, therefore, movable relative to fixed press frame member 57. Said platen may be held against rotation on the axis of the ram. A guide pin 65' operating in a bushed guide 66 in member 57 serves to hold the platen against such rotation. Thus, a die part carried by platen 64 may be retained in register with a die part carried by the bed of the press of which member 57 is part.

The booster 9 comprises a cylinder 7% that has body 59 as one head and is provided with an oppositely disposed head 7 i, an air piston 72 operable in said cylinder and provided with a reduced plunger 73 that operates in cylindrical passage 52, and a spring 74 to bias said piston and plunger in adirection toward the head 71.

A master valve 75 is connected to head 71 and conveys and exhausts pressure air into and out of the chamber 76' between head 71 and piston 72; Valve 75 is vented to the atmosphere through vent 75a. The chamber 77, between body 51 and piston 72, is vented as by a passage 78.

The air pressure source it) is connected to four-way valve 11 by a line 89 and, through said valve, by a line 81 to master valve 29 and by a line 82 to fitting or connection 43-01 valve 6. Pipe 63, a branch of line 82, is provided with a check valve 83 and an adjustable relief valve 84,

jected to the position in the lower portion of Fig. 2.

the latter between the check valve and the connection to air chamber 62 of cylinder 55. Valve 11 further'includes an air exhaust S5. Said valve is shown as operable by a handle 86 whichjs typical of any desired form of valveoperating means. I t a The three-way valve 12'is connected to source 1t by a line 87 and, when opened by operation of button 88, communicates line 87 with a line 89 extending to master valve 75.-

- t it 1 Operation a From the position of the parts in Fig. 1, the valve handle 86 is manipulated to connect the air source through line 80 to line 81 and thereby open quick-opening master valve 29'and admit the prsesure of source 19 into cylinder 20; -Piston 23 is depressed and displaces hydraulic fluid 27 through connection 30 into chamber 36. This pressure is great enough to overcome the light biasing force of springs 42-and open valve 37. The fluid'is thus forced into chamber 51 and thence into chamber 61 of hydraulic cylinderSS; The fluid will also fill bore 52. air pressure provided by source 10 is applied to ram piston 58 and the ram 59 and its platen 64 are, therefore, pro- The projection of the ram may be arrested short of the substantially' full projection shown. When the ram' cannot be further moved by the air force applied, valve 37 automatically closes because within the system a state of equal pressure throughout exists. 7

Now the three-way valve 12 is operated by depressing button 88 and opening the pressure of the source 10 to lines 87 and 89 and applying said pressure through quickopening master valve 75 to chamber 76 of the booster 9. If there should be. a drop in the pressure in lines 80 and 81 as a result of this operation, valve 37 will be closed to serve as a check against loss of pressure in chamber 61 of cylinder 55. a

Uponopening of valve 12, piston 72 is projected by air line pressure against the light force of spring 74. The total pressure on the relatively large piston 72 imposes the same total pressure on plunger 73. Since the latter is relatively smaller than piston 72, the unit pressure created by plunger 73 on the fluid in chamber 61'is relatively greater than'the unit pressure on piston 72. The differential of unit pressures is in direct ratio to the difference in areas between piston 72 and plunger 73.

In this manner, the initial pressure in unit 8 is boosted by operations-of valve 12 and this operation may be repeated as many times as desired. Each time the ram is further projectedlunder. the high force imposed by the booster and the booster is retracted by venting line 89 through valve 12, valve 37 automatically opens to admit additional fiuid from'the reservoir 5 into cylinder chamber 61. Consequently, by the intermittent application of the booster power, the ram may be intermittently projected to perform powerful work.

During the foregoing projectionof the ram, annulus 62 is vented through the pressure relief valve 84 which may be adjusted accordingly. 1 j

While not so shown, the button 88 may be inthe path of movement of valvehandle 86 and operated thereby, or the valve12 may be so interconnected with valve 11 as to be operable, when desired, by a single control, as handle a 86, or a number of selective controls either manually or automatically operated.

When retraction of the ram is to be instituted, handle 86' Thus, the

4 source 10 to annulus 62 and thereby causes the ram and platen to be retracted, Such retraction displaces the iluid past the open poppet valve and results in restoring piston 23 of reservoir 5 to the retracted position of Fig. 1. This new position of valve 11 exhausts line 81 through said valve and allows the described retraction of piston 23.

Since relief valve 84 may be adjusted to open only under the force projecting the ram, the latter will remain retracted by the air in annulus 62 and held by check valve 83. Consequently, the speed of'movement of the down stroke of the ram may be controlled by regulation of valve 84.

In the modification of Fig. 3, the ram cylinder 55a is carried by the press frame member 57 in'a manner similar valve has its inlet connected to port a, its outlet, to port through line 82 and fitting against piston 46 after the 1 valve 12 has been manipulated to allow spring 74- to retract piston 72 and plunger 73. I Since the pressure in cylinder 7 chamber 61 is now the same as the pressure of source 10, the la'rgerarea of piston 48, impinged by the pressure of source 10, overcomes any pressure there may be on poppet valve 37 and said valve opens (Fig. 2).

Simultaneously, line 63 conducts the pressure of the to that above described, the ram 5% operating in said cylinder, mounting a piston 58a, and defining an annulus 62a between said piston and the sealing gland 60a. The line 63a connectsto said cylinder 55a as described for line 63; V

In the above power unit construction 8a (comparable to unit 8) is incorporated the reservoir 5a, the ram 59a being made hollow to constitute a cylinder Ztla and provided with a piston 23a that is projectable by pressure air admitted through a line 81a. The tube 24a is the counterpart of stem 24. V

Chamber 61a is in direct communication with chamber Slawhich, by a port 95, may be connected to a pilotoperated check valve comparable to valve 6. Said check 95, and is air-operated, as described for valve 6.

The booster 9a is substantially similar to booster 9 and the corresponding parts are designated by like reference numbers with the suffix a. i

In this construction, the piston 58a of the ram 59a is provided with an outwardly-opening check poppet 96.

Operation of Fig. 3

The chamber 20a being filled with hydraulic fluid and the parts retracted as shown, line air is supplied, as before, at 81a. This pressure air projectspiston 23a in an upward direction, displaces fluid in chamber 20a through tube 24a, and connection 3tta,-into valve 6. This pressure opens poppet 37 and directs fluid under pressure, through port and chamber 51a, into a cylinder chamber 61a;

' -The ram 59a is thus projected and retained projected bebooster plunger 73a, theair pressure at 81a, acting on' piston 23a, displaces replenishing fluid past check valve 6 into chamber 61a. 7 V

When the" ram is to be retracted, air pressure is pro vided to open the poppet 37 of valve 6, as before, and simultaneouslyadmitted into annulus 62a through connection 63a. The ram retracts and in the process displaces fiuid from chamber 61a pastthe open poppet valve 37 into cylinder 29a, causing simultaneous retraction of piston 23:: to its low position in the ram.

While the foregoing has illustrated and described what are now contemplated to bethe best modes of carrying out the invention, the constructions are, of course, subject to modification without departing from the spirit and scope of the invention. It is, therefore, not desired to restrict the invention to the particular forms of. construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims. t

Havingthus described thein vention, what is claimed end. operable in said cylinder the opposite end of the ram-projeating beyond said cylinder and mounting:pres- --sure-applying means, a hydraulicfluid reservoir provided with an air-projectable piston-to-displace'said fluid from the reservoir, a check valve opening to flow 'from said reservoir, a body'mounted in the end of'said cylinder adjacent the piston, passagemeans conducting said flow through said body to said stationary cylinder "to project the ram, a booster cylinder within said bodyin communication with the ram cylinder, aplungeriitted into said booster cylinder, a pneumatically-operated piston larger than said plunger and aflixed to the plunger to impose increased pressure on the fluidin the ram cylinder while said check valve remains closed, 'and pneumatic pressure means toopen saidtcheck valve .torelieve the pressure in theram cylinder.

Hydro-pneumatic press apparatus according to claim 1: means to seal around the ram and carried by the open end of the ram cylinder, an annular chamber being defined-between said sealingmeans and the piston on the ram, and means to introducepneumatic pressure in said annular chamber to controlthe'rate of projection of said ram.

ydr rueumatic press apparatus co p tionary cylinder, a ram provided with a piston at one end operable in said cylinder, the opposite end of the ram projecting beyond said cylinder and mounting pressureapplying means, a hydraulic fluid reservoir provided with an air-projectable piston to displace said fluid from the reservoir, a check valve opening to flow from said reservoir, a body mounted in the end of said cylinder adjacent the piston, passage means conducting said flow through said body to said stationary cylinder to project the ram, a booster cylinder within said body in communication with the ram cylinder, a plunger fitted into said booster cylinder, a pneumatically-operated piston larger than said plunger and affixed to the plunger to impose increased pressure on the fluid in the ram cylinder while said check valve remains closed, pneumatic pressure means to open said check valve to relieve the pressure in the ram cylinder, means to seal around the ram and carried by the open end of the ram cylinder, an annular chamber being defined between said sealing means and the piston on the ram, and means to introduce pneumatic pressure in said annular chamber simultaneously with application of the pneumatic pressure to the means which opens the check valve to cause retraction of the ram while said check valve is open.

4. Hydro-pneumatic press apparatus comprising a stationary cylinder, a ram provided with a piston at one end operable in said cylinder, the opposite end of the ram projecting beyond said cylinder and mounting pressureapplying means, a hydraulic fluid reservoir provided with an air-projectable piston to displace said fluid from the reservoir, a check valve opening to flow from said reservoir, a body mounted in the end of said cylinder adjacent the piston, passage means conducting said flow through said body to said stationary cylinder to project the ram, a booster cylinder within said body in communication with the ram cylinder, a plunger fitted into said booster cylinder, a pneumatically-operated piston larger than said plunger and affixed to the plunger to impose increased pressure on the fluid in the ram cylinder while said check valve remains closed, pneumatic pressure means to open said check valve to relieve the pressure in the ram cylinder, means to seal around the ram and carried by the open end of the ram cylinder, an annular chamber being defined between said sealing means and the piston on the ram, means to introduce pneumatic pressure in said annular chamber simultaneously with application of the pneumatic pressure to the means which opens the check valve to cause retraction of the ram while said check valve is open, a common valve-controlled line for the pneumatic means controlling retraction of the ram and holding the check valve open, and an adjustable pressure relief valve in the line between said annular chamber and the valve c'ontrdllin'g pneumatic pressure to'control the speed of the stroke of the ram 'tionary cylinder, a ram provided-With a piston at one end operable 'in said cylinder, the opposite end of the ram projecting beyond said cylinder and mounting pressureapplying'means, a hydraulic fluid reservoir provided with an air-projectable piston to displace said fluid from the reservoir, said reservoir being provided within the ram, 21 check valve opening to flow from said reservoir, a body mounted in the end of said cylinder adjacent the piston, passage means conducting said flow through said'body to said stationary cylinder to project the ram, 'a booster cylinder within said body incommunication with the ram cylinder, a plunger fitted into said booster cylinder, a pneumatically-operated piston larger than said plunger and atfixed to the plunger to impose increased pressure on the fluid in the ram cylinder while said check valve remains closed, and pneumatic pressure means to open said check valve to relieve the pressure in the ram cylinder.

6. Hydro-pneumatic press apparatus comprising a stationary cylinder, a ram provided with a piston at one end operable in said cylinder, the opposite end of the ram projecting beyond said cylinder and mounting pressure-applying means, a hydraulic fluid reservoir provided with an air-projectable piston to displace said fluid from the reservoir, said ram being hollow and constituting the mentioned reservoir, a check valve-controlled opening communicating the ram hollow and the stationary cylinder, a check valve opening to flow from said reservoir, passage means conducting said flow to said stationary cylinder to project the ram, a booster cylinder in communication with the ram cylinder, a plunger fitted into said booster cylinder, a pneumatically-operated piston larger than said plunger and aflixed to the plunger to impose increased pressure on the fluid in the ram cylinder while said check valve remains closed, and pneumatic pressure means to open said check valve to relieve the pressure in the ram cylinder.

7. In combination, a hydraulic fluid reservoir, a pilotoperated check valve to receive fluid from said reservoir and provided with a poppet that opens under pressure of said fluid, a power-applying unit comprising a ram and a cylinder in which said ram is movable, said cylinder being receptive of fluid flowing past the open poppet in the valve, a pneumatically-operated hydraulic booster unit to increase the fluid pressure in the ram cylinder, said fluid being retained within said cylinder by the mentioned poppet when closed, and independent pneumatically-operated means to open said poppet against the pressure within said cylinder.

8. In combination, a hydraulic fluid reservoir, a pilotoperated check valve to receive fluid from said reservoir and provided with a poppet that opens under pressure of said fluid, a power-applying unit comprising a ram and a cylinder in which said ram is movable, said cylinder being receptive of fluid flowing past the open poppet in the valve, a pneumatically-operated hydraulic booster unit to increase the fluid pressure in the ram cylinder, said fluid being retained within said cylinder by the mentioned poppet when closed, and pneumatically-operated means to open said poppet against the pressure within said cylinder and simultaneously move the ram in a direction to displace the fluid past the open poppet and back into the reservoir.

9. Hydro-pneumatic pressure apparatus comprising a fluid reservoir, a piston within said reservoir, a pilotoperated check valve controlling flow of fluid to and from said reservoir, 21 source of air pressure, said check valve having a poppet operated by air pressure from said source and by fluid pressure within said reservoir, a ram cylinder, a ram operable with said cylinder, said ram having a piston at one end thereof, a body attached to said cylinder adjacent said piston, said body having a booster cylinder in communication with the ram cylinder and a fluid passage therein connecting said cylinder to fluid flowing from said check valve, a second cylinder attached to said body oppositesaid ram cylinder, a piston within said second cylinder, at plunger attached to said piston, said plunger being mounted to slide within the booster cylinder in said body to increase the fluid pressure Within'said ram cylinder, and pneumatic means to move the pistons within the -reservoir and the second cylinder to project said ram, said pneumatic means also being connected to open the poppet in the check valve and simultaneously retract said ram and hold it in retracted position until the next cycle of operation.

10. Hydro-pneumatic pressureapparatus comprising a fluid reservoir, a piston within said reservoir, a pilotoperated check valve controlling flow of fluid to and from said reservoir, a source of air pressure, said check valve having a poppet operated by air pressure from said source and by fluid pressure Within said reservoir, a body having a fluid passage therein connected to fluid flowing from said check valve, said body having a booster cylinder therein, a pair of cylinders attached to said body, each of said cylinders having ,a piston slidable therein,

.the piston in one cylinder having a plunger attached thereto and slidable within said booster cylinder and the piston in the second cylinder having a ram attached thereto, and pneumatic means to move the pistons in the reservoir and in the one cylinder to cause fluid to flow past said check'valve and create pressure on the piston in the second cylinder to project said ram, said pneumatic means also being connected to open the poppet in said check valve and simultaneously retract said ram and hold it in retracted position until the next cycle of operaticn.

References Cited in the file of this patent UNITED STATES PATENTS 

